Meteor Shower Calendar 2018

Here’s our meteor shower calendar for 2018.  It is sourced from the IMO’s Working List of Visual Meteor Showers (https://www.imo.net/files/meteor-shower/cal2018.pdf, Table 5, p. 25).

Each meteor shower is identified using its three-character IAU meteor shower code.  Codes are bold on the date of maximum, and one day either side of maximum.

Here’s a printable PDF file of the meteor shower calendar shown below:

Meteor Shower Calendar 2018

Happy meteor watching!

January 2018
SUN MON TUE WED THU FRI SAT
1
DLM QUA
2
DLM QUA
3
DLM QUA
4
DLM QUA
5
DLM QUA
6
DLM QUA
7
DLM QUA
8
DLM QUA
9
DLM QUA
10
DLM QUA GUM
11
DLM QUA GUM
12
DLM QUA GUM
13
DLM GUM
14
DLM GUM
15
DLM GUM
16
DLM GUM
17
DLM GUM
18
DLM GUM
19
DLM GUM
20
DLM GUM
21
DLM GUM
22
DLM GUM
23
DLM
24
DLM
25
DLM
26
DLM
27
DLM
28
DLM
29
DLM
30
DLM
31
DLM ACE
February 2018
SUN MON TUE WED THU FRI SAT
1
DLM ACE
2
DLM ACE
3
DLM ACE
4
DLM ACE
5
ACE
6
ACE
7
ACE
8
ACE
9
ACE
10
ACE
11
ACE
12
ACE
13
ACE
14
ACE
15
ACE
16
ACE
17
ACE
18
ACE
19
ACE
20
ACE
21 22 23 24
25
GNO
26
GNO
27
GNO
28
GNO
March 2018
SUN MON TUE WED THU FRI SAT
1
GNO
2
GNO
3
GNO
4
GNO
5
GNO
6
GNO
7
GNO
8
GNO
9
GNO
10
GNO
11
GNO
12
GNO
13
GNO
14
GNO
15
GNO
16
GNO
17
GNO
18
GNO
19
GNO
20
GNO
21
GNO
22
GNO
23
GNO
24
GNO
25
GNO
26
GNO
27
GNO
28
GNO
29 30 31
April 2018
SUN MON TUE WED THU FRI SAT
1 2 3 4 5 6 7
8 9 10 11 12 13 14
LYR
15
PPU LYR
16
PPU LYR
17
PPU LYR
18
PPU LYR
19
ETA PPU LYR
20
ETA PPU LYR
21
ETA PPU LYR
22
ETA PPU LYR
23
ETA PPU LYR
24
ETA PPU LYR
25
ETA PPU LYR
26
ETA PPU LYR
27
ETA PPU LYR
28
ETA PPU LYR
29
ETA LYR
30
ETA LYR
May 2018
SUN MON TUE WED THU FRI SAT
1
ETA
2
ETA
3
ELY ETA
4
ELY ETA
5
ELY ETA
6
ELY ETA
7
ELY ETA
8
ELY ETA
9
ELY ETA
10
ELY ETA
11
ELY ETA
12
ELY ETA
13
ELY ETA
14
ARI ELY ETA
15
ARI ETA
16
ARI ETA
17
ARI ETA
18
ARI ETA
19
ARI ETA
20
ARI ETA
21
ARI ETA
22
ARI ETA
23
ARI ETA
24
ARI ETA
25
ARI ETA
26
ARI ETA
27
ARI ETA
28
ARI ETA
29
ARI
30
ARI
31
ARI
June 2018
SUN MON TUE WED THU FRI SAT
1
ARI
2
ARI
3
ARI
4
ARI
5
ARI
6
ARI
7
ARI
8
ARI
9
ARI
10
ARI
11
ARI
12
ARI
13
ARI
14
ARI
15
ARI
16
ARI
17
ARI
18
ARI
19
ARI
20
ARI
21
ARI
22
JBO ARI
23
JBO ARI
24
JBO ARI
25
JBO
26
JBO
27
JBO
28
JBO
29
JBO
30
JBO
July 2018
SUN MON TUE WED THU FRI SAT
1
JBO
2
JBO
3
CAP
4
CAP
5
CAP
6
CAP
7
CAP
8
CAP
9
CAP
10
CAP
11
CAP
12
CAP SDA
13
CAP SDA
14
CAP SDA
15
CAP SDA PAU
16
CAP SDA PAU
17
PER CAP SDA PAU
18
PER CAP SDA PAU
19
PER CAP SDA PAU
20
PER CAP SDA PAU
21
PER CAP SDA PAU
22
PER CAP SDA PAU
23
PER CAP SDA PAU
24
PER CAP SDA PAU
25
PER CAP SDA PAU
26
PER CAP SDA PAU
27
PER CAP SDA PAU
28
PER CAP SDA PAU
29
PER CAP SDA PAU
30
PER CAP SDA PAU
31
PER CAP SDA PAU
August 2018
SUN MON TUE WED THU FRI SAT
1
PER CAP SDA PAU
2
PER CAP SDA PAU
3
KCG PER CAP SDA PAU
4
KCG PER CAP SDA PAU
5
KCG PER CAP SDA PAU
6
KCG PER CAP SDA PAU
7
KCG PER CAP SDA PAU
8
KCG PER CAP SDA PAU
9
KCG PER CAP SDA PAU
10
KCG PER CAP SDA PAU
11
KCG PER CAP SDA
12
KCG PER CAP SDA
13
KCG PER CAP SDA
14
KCG PER CAP SDA
15
KCG PER CAP SDA
16
KCG PER SDA
17
KCG PER SDA
18
KCG PER SDA
19
KCG PER SDA
20
KCG PER SDA
21
KCG PER SDA
22
KCG PER SDA
23
KCG PER SDA
24
KCG PER
25
KCG
26 27 28
AUR
29
AUR
30
AUR
31
AUR
September 2018
SUN MON TUE WED THU FRI SAT
1
AUR
2
AUR
3
AUR
4
AUR
5
SPE AUR
6
SPE
7
SPE
8
SPE
9
DSX SPE
10
STA DSX SPE
11
STA DSX SPE
12
STA DSX SPE
13
STA DSX SPE
14
STA DSX SPE
15
STA DSX SPE
16
STA DSX SPE
17
STA DSX SPE
18
STA DSX SPE
19
STA DSX SPE
20
STA DSX SPE
21
STA DSX SPE
22
STA DSX
23
STA DSX
24
STA DSX
25
STA DSX
26
STA DSX
27
STA DSX
28
STA DSX
29
STA DSX
30
STA DSX
October 2018
SUN MON TUE WED THU FRI SAT
1
STA DSX
2
ORI STA DSX
3
ORI STA DSX
4
ORI STA DSX
5
ORI STA OCT DSX
6
ORI STA DRA OCT DSX
7
ORI STA DRA OCT DSX
8
ORI STA DRA DSX
9
ORI STA DRA DSX
10
ORI DAU STA DRA
11
ORI DAU STA
12
ORI DAU STA
13
ORI DAU STA
14
ORI EGE DAU STA
15
ORI EGE DAU STA
16
ORI EGE DAU STA
17
ORI EGE DAU STA
18
ORI EGE DAU STA
19
LMI ORI EGE STA
20
NTA LMI ORI EGE STA
21
NTA LMI ORI EGE STA
22
NTA LMI ORI EGE STA
23
NTA LMI ORI EGE STA
24
NTA LMI ORI EGE STA
25
NTA LMI ORI EGE STA
26
NTA LMI ORI EGE STA
27
NTA LMI ORI EGE STA
28
NTA ORI STA
29
NTA ORI STA
30
NTA ORI STA
31
NTA ORI STA
November 2018
SUN MON TUE WED THU FRI SAT
1
NTA ORI STA
2
NTA ORI STA
3
NTA ORI STA
4
NTA ORI STA
5
NTA ORI STA
6
LEO NTA ORI STA
7
LEO NTA ORI STA
8
LEO NTA STA
9
LEO NTA STA
10
LEO NTA STA
11
LEO NTA STA
12
LEO NTA STA
13
NOO LEO NTA STA
14
NOO LEO NTA STA
15
NOO AMO LEO NTA STA
16
NOO AMO LEO NTA STA
17
NOO AMO LEO NTA STA
18
NOO AMO LEO NTA STA
19
NOO AMO LEO NTA STA
20
NOO AMO LEO NTA STA
21
NOO AMO LEO NTA
22
NOO AMO LEO NTA
23
NOO AMO LEO NTA
24
NOO AMO LEO NTA
25
NOO AMO LEO NTA
26
NOO LEO NTA
27
NOO LEO NTA
28
PHO NOO LEO NTA
29
PHO NOO LEO NTA
30
PHO NOO LEO NTA
December 2018
SUN MON TUE WED THU FRI SAT
1
PUP PHO NOO NTA
2
PUP PHO NOO NTA
3
HYD PUP PHO NOO NTA
4
GEM HYD PUP PHO NOO NTA
5
DLM GEM HYD MON PUP PHO NOO NTA
6
DLM GEM HYD MON PUP PHO NOO NTA
7
DLM GEM HYD MON PUP PHO NTA
8
DLM GEM HYD MON PUP PHO NTA
9
DLM GEM HYD MON PUP PHO NTA
10
DLM GEM HYD MON PUP NTA
11
DLM GEM HYD MON PUP
12
DLM COM GEM HYD MON PUP
13
DLM COM GEM HYD MON PUP
14
DLM COM GEM HYD MON PUP
15
DLM COM GEM HYD MON PUP
16
DLM COM GEM MON
17
DLM URS COM GEM MON
18
DLM URS COM MON
19
DLM URS COM MON
20
DLM URS COM MON
21
DLM URS COM
22
DLM URS COM
23
DLM URS COM
24
DLM URS
25
DLM URS
26
DLM URS
27
DLM
28
DLM QUA
29
DLM QUA
30
DLM QUA
31
DLM QUA

The Good Old Days of Astronomy…

Those of you who grew up in the 1950s and 1960s as I did will especially delight in reading the July 7, 2007 entry of Uncle Rod’s Astro Blog, courtesy of Alabama astronomer Rod Mollise.  What a hoot!

And here’s a note from Phil Harrington’s website about Celestron’s ads in the 1990s: “It must be good to be an amateur astronomer in California, judging by the ads run by Celestron over the years…Yup, just another typical club star party, right?”  Photo montage by Rod Mollise.

Plastic Recycling

That number you see within the recycling symbol on recyclable plastic is called the “resin identification code” or RIC.  One pet peeve: the recycling symbol and RIC are often too small, not easy to see, or are difficult to find.  Also, some plastics and plastic parts that could be recycled are not labeled.

The seven different types of recyclable plastics are listed below, along with a small subset of initial and recycling uses.  New applications for recycled plastics are being invented all the time!  Perhaps you have some ideas.

Polymer: Polyethylene terephthalate (C10H8O4)n
Other names & abbreviations: PETE, PET, polyester
Common uses: beverage bottles, fibers for clothing
Recycling uses: non-food containers, strapping, carpet fiber

Polymer: High-density polyethylene (C2H4)n
Other names & abbreviations: HDPE, PE-HD
Common uses: milk jugs, food containers
Recycling uses: plastic lumber, parking bumpers, recycling bins, sheds

Polymer: Polyvinyl chloride (C2H3Cl)n
Other names & abbreviations: PVC, V
Common uses: bottles, non-food packaging
Recycling uses: pipes, fencing, flooring, lawn chairs, wire insulation

Polymer: Low-density polyethylene (C2H4)n
Other names & abbreviations: LDPE, PE-LD
Common uses: plastic bags, six-pack rings, containers, snap-on lids
Recycling uses: packaging foam, plastic film, garbage bags

Polymer: Polypropylene (C3H6)n
Other names & abbreviations: PP
Common uses: food containers, medical & lab equipment, pill bottles
Recycling uses: pallets, trays, landscape borders, compost bins, bike racks

Polymer: Polystyrene (C8H8)n
Other names & abbreviations: PS
Common uses: plastic cutlery, disposable razors, CD & DVD cases
Recycling uses: packaging material, insulation sheets, park benches

Polymer: Other Plastics (acrylic, nylon, polycarbonate, etc.)
Other names & abbreviations: OTHER, O
Common uses: plastic lenses, food packaging & bottles, LCD screens, etc.
Recycling uses: plastic lumber, bus shelters, traffic lights, signs, etc.

Big Binoculars

It is often said (and rightfully so) that your first telescope should be a pair of binoculars.  And your second pair of binoculars should be big binoculars on a hands-free binocular mount.  It is amazing how much you can see (and how beautiful it is) at a dark-sky location with 16 x 70 binoculars mounted on an Orion Monster Parallelogram Binocular Mount & Tripod, for example.

And then there’s the realm of binocular telescopes, such as a 6, 10, or 16″ Reverse Binocular Telescope from JMI.  As famed astrophotographer Tony Hallas says in a letter in the July 2007 issue of Sky & Telescope, “Daphne and I have observed…many…deep-sky objects many times over the years using conventional telescopes, including very big ones.  Neither of us ever wants to go back to monocular observing.  Looking with both eyes through twin scopes with fast optical systems enables the brain to absorb so much more information—it’s utterly breathtaking.”

Vacuum Telescopes

The light from a celestial object is bounced and distorted as it penetrates the Earth’s turbulent atmosphere, and this image degradation continues all the way into the telescope.  Currents of air within the telescope tube caused by parts of the tube or optics being at different temperatures can severely degrade a telescope image, particularly in a large telescope.

Nowhere is this more apparent than in a professional solar telescope.  Sunlight entering the telescope heats up the inside of the telescope and optical components, resulting in turbulent air currents that make the images less sharp than they could be.

To solve this problem, some solar telescopes contain a vacuum so there is no air to heat and therefore no image distortion within the telescope.  This requires, however, a rather thick piece of glass (of high optical quality, of course) at the front of the telescope in order to maintain the vacuum within the tube.  A good example of this kind of telescope is the Swedish 1-m Solar Telescope (SST) located on the island of La Palma in the Canary Islands.

A much thinner front lens can be used if the telescope tube is filled with helium rather than evacuated, and though the results are much better than an air-filled telescope tube, they are not quite as good as with a vacuum telescope.

I am not aware of any vacuum telescopes being used for nighttime observations.

Meteor Watcher’s Network

I’ve been a meteor watching enthusiast since at least the early 1980s.  I had the good fortune back then of getting to know Paul Martsching when we both lived in Ames, Iowa, and few people in the world have logged more hours in the name of meteor science than he.  We have been close friends ever since.

We’ve learned that here in the U.S. Midwest, for any given astronomical event you wish to observe, there is between a 2/3 and 3/4 chance that it will be clouded out—unless you are willing to travel.  Weather forecasting has gotten much better over the years, and nowadays you can vastly improve your chances of not missing that important astronomical event, such as the Perseid meteor shower in August or the Geminid meteor shower in December.

Paul and I have traveled from Ames, Iowa to Nebraska, South Dakota, North Dakota, Kansas, Missouri, and Illinois over the years to escape cloudy skies.  Just last year, we had to travel to north of Jamestown, North Dakota to see the Perseids, and this year it appears we will need to travel to southern Kansas, Oklahoma, or Arkansas to get a clear view of the Geminids.

Weather forecasts don’t begin to get really accurate until about 48 hours out, so we often have to decide at nearly the last minute where to travel.  Therein lies the problem.  Where can we find a safe observing spot to put down our lawn chairs where there are no terrestrial lights visible brighter than the brightest stars, and no objectionable skyglow from sources or cities over the horizon?  It is a tall challenge.

What we need to develop is a nationwide network of folks who know of good places to watch meteors.  This would include astronomy clubs, individual astronomy enthusiasts, managers of parks and other natural areas, rural land owners who would allow meteor watchers on their land, rural B&Bs, cabins, lodges, ranches, and so on.  Once you know where you need to go to get out from under the clouds, there would be someone you could call in that area of the country to make expeditious observing arrangements for that night or the following night.  And perhaps lodging as well, if available.

If you would like to work with me to build a meteor watcher’s network or have ideas to share, please post comments here or contact me directly.

Do Dark Matter and Dark Energy Exist?

Numerous searches for the particle or particles responsible for dark matter have so far come up empty.  What if dark matter doesn’t really exist?  Could there be alternative explanation for the phenomena attributed to dark matter?

In the November 10, 2017 issue of the Astrophysical Journal, Swiss astronomer André Maeder presents an intriguing hypothesis that non-baryonic dark matter need not exist, nor dark energy either.  In “Dynamical Effects of the Scale Invariance of the Empty Space: The Fall of Dark Matter?” he suggests that scale invariance of empty space (i.e. very low density) over time could be causing the phenomena we attribute to dark matter and dark energy.

What is scale invariance?  In the cosmological context, it means that empty space and its properties do not change following an expansion or contraction.  Scales of length, time, mass, energy, and so on are defined by the presence of matter.  In the presence of matter, space is not scale invariant.  But take the matter away, and empty space may have some non-intuitive properties.  The expanding universe may require adding a small acceleration term that opposes the force of gravity.  In the earlier denser universe, this acceleration term was tiny in comparison to the rate at which the expansion was slowing down, but in the later emptier universe, the acceleration term dominates.  Sound like dark energy, doesn’t it?  But maybe it is an inherent property of empty space itself.

The existence of dark matter is primarily suggested by two  observed dynamical anomalies:

  1. Flat outer rotation curve of spiral galaxies (including the Milky Way)
  2. Motions of galaxies within galaxy clusters

Many spiral galaxies have a well-known property that  beyond a certain distance from their centers, their rotation rate (the orbital velocity of stars at that distance) stays nearly constant rather than decreasing as one would expect from Keplerian motion / Newtonian dynamics (think planets orbiting the Sun in our own solar system— the farther the planet is from the Sun, the slower it orbits).  Only there seems to be evidence that the rotation curves of galaxies when they are young (as seen in the high-redshift universe) do have a Keplerian gradient, but in the present-day universe the rotation curve is flat.  So, it appears, flat rotation curves could be an age effect.  In other words, in the outer regions of spiral galaxies, stars may be orbiting at the same velocity as they did in the past when they were closer to the galactic center.  Maeder writes:

…the relatively flat rotation curves of spiral galaxies is an age effect from the mechanical laws, which account for the scale invariant properties of the empty space at large scales.  These laws predict that the circular velocities remain the same, while a very low expansion rate not far from the Hubble rate progressively extends the outer layers, increasing the radius of the Galaxy and decreasing its surface density like 1/t.

We need to study the rotation curves (as a function of galactocentric radius all the way out to the outermost reaches of the galaxy) of many more galaxies at different redshifts (and thus ages) to help us test the validity of the scale invariant vs. dark matter hypotheses.  Maeder suggests a thorough rotation study of two massive and fast-rotating galaxies, UGC 2953 (a.k.a. IC 356; 50-68 Mly) and UGC 2487 (a.k.a. NGC 1167; 219-225 Mly), would be quite interesting.

The observed motions of galaxies within many galaxy clusters seems to indicate there is a substantial amount of unseen mass within these clusters, through application of the virial theorem.  However, the motions within some galaxy clusters such as Coma (336 Mly) and Abell 2029 (1.1 Gly) may be explainable without the need to resort to “exotic” dark matter.

Then there’s the AVR (Age-Velocity Dispersion Relation) problem which, incidentally, has nothing to do with dark matter.  But it may offer evidence for the scale invariant hypothesis.  It is convenient to specify the motion of a star in a spiral galaxy such as the Milky Way in a galactocentric coordinate system.

U = component of velocity towards the galaxy center

V = component of velocity in the direction of galactic rotation

W = component of velocity orthogonal to the galactic plane

Maeder writes:

The AVR problem is that of explaining why the velocity dispersion, in particular for the W-component, considerably increases with the age of the stars considered … Continuous processes, such as spiral waves, collisions with giant molecular clouds, etc… are active in the disk plane and may effectively influence the stellar velocity distributions.  However…vertical heating (the increase of the dispersion σW) is unexpected, since the stars spend most of their lifetime out of the galactic plane.

There may be more to “empty” space than meets the eye…

References
Maeder, A., 2017, ApJ, 849, 158
arXiv:1710.11425